Hydraulic pump or motor



F1115- I p Nov. 21, 1939. 4 5K. BENEDEK I 2,130,343

HYDRAULIC PUMP OR MOTOR Filed Nov. 20, 1935 7 Sheets-Sheet l mflw mm [l f f ELEKKEIENEDEK,

Nov. 21, 1939. E K.,BENEDEKI 2,180,

HYDRAULIC PUMP OR MOTOR Filed Nov. 20, 1935 7 Sheets-Sheet 2 ELER K- EENED EK NOV. 21, 1939. E BENEDEK 2,180,343

HYDRAULIC PUMP OR MOTOR Filed Nov. 20, 1955 7 Sheets-$heet 4 1-15-15- 3 ELEK K EJEN E 1:E-K,

Nov. 21, 1939. E. K. BENEDEK 2,180,343

HYDRAULIC PUMP OR MOTOR Filed Nov. 20, 1935 7 Sheets-Sheet 6 1 15-25- z fim alkgj ELEK. KEIENEDEK Patented Nov. 21, 1939 PATENT OFFICE nrnimnmc PUMP on Y MOTOR Elek K. .Benedek, Bucyrus, Ohio Application November 20, 1935, Serial No. 50,671 4 Claims. (01. 103-4 1 This invention relates to high pressure variable displacement, reversible, radial piston pumps and motors and particularly to eflicient driving and load connections between the piston and cylinder assemblies and the reactance means.

One of the principal objects of the present in vention is to provide a connection between the tons and associated reactance in which the mass and inertia of the reciprocating parts of the connection is so reduced that mass and inertiaforces resulting from high speed reciprocation are reduced to a-minimum.

A correlative object is to accomplish this result without a sacrifice in strength of the reciprocating parts. a

Another object is to reduce the number of parts necessary for the connectionbetween the piston and reactance to a minimum. I

Another and more general object is to provide for anti-friction driving transmission between the barrel and the reactance in a manner such that high efiiciency can be provided at high commercial pressures and speed and accurate synchronization of the speeds of the rotors can be maintained under all conditions of operation.

Other objects and advantages will become apparent from the following specification wherein reference is made to the drawings in which Fig. 1 is a longitudinal sectional view of a pump or motor embodying the principles of the present invention;

Fig. 2 is a cross sectional view taken on the plane indicated by the line 2-2 of Fig. 1;

Fig. 3 is a fragmentary sectional view of the piston head and associated reactance rings and is taken ona plane indicated by the line 3-3 in Fig. 2; r

Fig. 4 is an elevation of a pistonand crosspins illustrating the geometric relations thereof;

Fig. 5 is an elevation of a piston and crosspin illustrating a slight modification of the structure of Fig.4;

Fig. 6 is a fragmentary elevation of a reactance ring used in connectionwith the piston structure of Fig. 5;

Figs. 7 and '8 are diagrammatic. illustrations showing comparatively certain stress relations of the priorart and present piston head structure;

Fig. 9 is a fragmentary sectional view similar to Fig. 2 illustrating a modified piston head .and reactance combination Fig. 10 is a cross sectional view taken on a plane indicated by the line Ill- 0 in Fig. 9;

Fig. 11 is a sectional view taken on the plane indicated by the line ll-ll in Fig. 10;

viull complement tapered rollers .Fig. 12 is a fragmentary view of the reactance ring shown in Fig. 11 illustrating certain operating characteristics andrelations of the ring and crosspins for load and torque transmission; Fig. 13 is a longitudinal sectional view of a pump or motor illustrating a modified piston head and reactance combination and is taken on a plane indicated by the line l3--l3 in Fig. 14;

Fig. 14 is a cross sectional view taken on the plane indicated by the line "-44 in Fig. 13;

Figs. 15 and 16 are an elevation and plan view respectively of one of the pistonsand crossheads of Fig. 14;' Y

Fig. 17 is a longitudinal cross sectional view of part of a pump or motor structure and is taken on a plane indicated by the line I lll of Fig. 18;

Fig. 18 is a cross sectional view taken on a plane indicated by the line iii-l8 of Fig. 17

Fig. 19 is an elevation of one of the pistons and associated heads of Fig. 18;

Fig. 20 is a fragmentary plan view of a portion of the barrel and associated piston of Fig. 18 as viewed from the planeindicated by the line 20-20 of Fig. 18;

Fig. 21 is a cross sectional view taken on a plane indicated by the line 2l-2lin Fig. 13 and illustrates the barrel mounting thereof and of motors .oi the oscillating radial crosshead type, i being apparent therefrom. Thepump includes a rigid weight supporting. casing i, in which is mounted a valve pintle 2, having reversible valve ports 3 and 4 for valving cooperation with the cylinders, later to be described. The ports 3 and 4 are connected by suitable pairs of ducts 5 and 6' respectively with diametrically opposite main ports "I and 8 respectively in the pintle, the main ports, in turn, being connected through suitable ducts, not shown, formed in the housing l .with

an external fluid circuit.

A cylinder barrel l0 having an axial bore Illa is rotatably mounted in the casing on heavy duty ll, arranged one set at each end of the barrel and securing the 55 barrel in fixed axial and radial position within the housing. Positive but slight radial clearance between the barrel bore and pintle 2 is maintained by sets of elongated free rollers l2 and I3 respectively, arranged one set at each end of the pintle and operating on raceways formed directly on the pintle.

The barrel has a plurality of radial cylinders l4, each having a cylinder port l5 for cooperation successively with the ports 3 and 4 as the barrel rotates.

Mounted one in each cylinder are pistons l6, each having an enlarged head I? elongated fore and aft from the axis of the associatedpiston, and of greater dimension radially of the pump or motor than transversely, that is, than parallel to the rotative axis. Each head I1 is preferably formed integral with the associated piston and has an elongated chordal operating way Ila by which it is associated with the rotary reactance through the medium of thrust pins I8 in rolling engagement with the'way Fla. The operating way Fla is preferably in separate fore and aft portions, a reinforcing bridge llb being left therebetween to provide additional rigidity.

The rotary reactance comprises a pair of' axially spaced rings l9 disposed one at each of the lateral faces of the piston heads, the rings being secured together in coaxial relation with each other by means of suitable bolts 20 and accurate spacing of the rings being maintained by spacing sleeve 2|, carried on the bolts 20. Thus the rings are drawn firmly into axially spaced relation to provide a circumferential recess accommodating the heads I! with operating clearance on y.

As better illustrated in Fig. 3, each of the crosspins l8. extends beyond the lateral limits of the associated head 11, the extending ends of each pin being rotatably mounted in aligned bores in the rings 19. For mounting the pins by their ends in the rings IQ for free rotation about their respective axes and for reducing the frictional resistance to rotation-of the end portions of the pins to an amount less .than the rolling frictional resistance of the mid portions in the ways IIa, the ends of the pins are mounted in capillary cageless needle rollers 22. The outer end por-, tions of the pins 18 extend beyond the outer radial faces of the rings 19 and are circumferentially recessed adjacent the plane of the outer radial faces of the rings for receiving suitable retaining means such as snap washers 24 which constrain the pins in cooperative relation with the rings and piston heads while permitting free rotation thereof. In the form illustrated, the washers 24 may also act as retaining washers for the needle bearings 22 at their outer ends. The rings l9, in turn, are mounted in an adjustable stator 25, both on the same set of elongated rollers 26 so that they-rotate therein freely and as a single unitary structure. Adjustment of the statorfor varying the eccentricity ofthe rings with respect to the barrel is effected through the medium of a control rod 21.

In the structure described, the piston heads I! and the slots therein must be made with extreme accuracy as also must the mounting of the pins in the rotary reactance rings [9 and all parts must be accurately assembled as the pins are fixedly secured in the rings and the pistons are fixed with respect to their associated crossheads,

since no provision is made for adjustment of the working parts after the assembly and the original manufacture and assembly of the barrel, cylinders, pistons, crossheads and pins must be maintained to the required accuracy for alignment.

Referring next to Figs. '7 and 8, one of the principal advantages of the present crossheads is diagrammatically illustrated. Heretofore the usual piston T-head, with which the present structure is most nearly comparable, when viewed in cross section as indicated. at A in Fig. 7, has its minor axis disposed parallel to the piston axis and consequently in the direction of load application, indicated by the arrow L. Its dimension, therefore, in the direction of load is far less than normal to the load. Obviously, the load, in the direction of the arrow L, tends to warp the head and is not as effectively resisted as in'the case of the present structure, illustrated in Fig. 8. In

this structure the head in cross section B has its major axis parallel to the piston axis or direction of load, indicated by the arrow M. a

The strength of a beam is proportional with its moment of inertia or section modulus, wherein b is the width and dis the depth in the direction of load application. It is apparent, therefore, that the present structure can withstand many times the load of the structure illustrated in Fig. 7 under similar stresses and with the same elastic or permanent deformation even though the cross section area A and B of the two heads are the same. Again, due to the greater section modulus for resisting the piston load, a much lighter construction may be used for the same load with heads made in accordance with the present invention. Again, due to the nature of section modulus, a head disposed such as in Fig. 8 is not appreciably weakened by the removal of material for forming the ways Ila as the ways are disposed close to and preferably symmetrical with respect to the neutral axis which is normal to the load, hereinafter referred to as the normal neutral axis. Consequently, ample material remains for both compression and tension remote from the normal neutral axis. Thus not only may the ways be provided without an appreciable weakening of the structure, but also the head structure is made lighter in weight so that inertia forces due to high speed reciprocation are greatly reduced. As a result, the present head structure and its relation to the piston load makes possible the connections between the head and secondary rotor which were not practicable with the heads heretofore used and such as illustrated in Fi 7.

The present design, however, requires precision and a disposition of the common plane X1-Xr of the axes of the crosshead pins normal to the axis X2X2 of the piston, as illustrated in Fig. 4, the plane X1X1 being the normal neutral axis of the crosshead.

In order to make an eflicient pump or motor, and provide for free rotation of the rolling pins l8 with respect to the rings [9, and free rolling engagement thereof with the head H, the rolling pins l8 must remain in the position wherein their axes are parallel and define a plane normal to the piston axis. Referring to Fig. 9, the requirement for this accurate relation is illustrated diagrammatically.

For providing this relation in manufacture, the ways l'la are formed accurately at right angles to the piston axis. The crosspins are to be positioned in the rotary reactance rings IS with their axes in a circle I, as illustrated inFig. 2, which is concentric with the rings IS, an operation which' may readily beaccomplished by the usual dividing head machine tool. All that is then necessary is to take precision dividers,

such as a compass, and measure to each side of the piston axis the same distance and the intersection of the are or line thus drawn with. the

accurate coaction and proper relative positions between the radial axis of the cylinders and the crosspins, as well as the chordal plane defined by the axes of the associated-crosspins, is provided.

As a result, emcient operation 'will not be (18! pendent upon self-aligning movement of any parts with respect to others but positive freedom is provided initially through the simple nature of the structure. This coaction is maintained as elastic and permanent deformations are ,very slight in the present heads. At the same time,

the layout and manufacture is comparatively simple.

Referring next to Figs. and 6, a somewhat similar cooperation is provided, the crosspins being rotatably mounted in the head of the piston with the operating ways in the reactance. For example, in Fig. 5 each piston has a crosshead 26 disposed with the major axis of its cross section parallel to the piston axis. Rolling thrust pins 21 are mounted on capillary rollers 28 in the head 26, the axis of the rollers 28 lying in a plane normal to the piston axis. In the cooperating reactance rings 29, .as illustrated in Fig. 6, are chordal ways 29a which likewise lie in the plane defined by the ends of the crosspins and accommodate the ends of the pins for rolling coaction therewith to compensate for tangent al components of eccentricity of the cylinder rotor and reactance rotor. Carrying the development a step further. there is illustrated in Figs. ,9 to 12 inclusive. a crosshead of this general characterhaving separate load transmitting and torque transmitting rolling pins. In this structure, a barrel 30 having radial cylinders 3! is provided, each cylinder 3| carrying a radial piston 32 having a head 33 corresponding in shape generally to the head I! heretofore described. The head 33 is also tapered from the mid portion toward the ends so as to provide as near as may be a constant strength Rotatably mounted in the head 33 with its axis intersecting the piston axis is a load transmitting rolling pin 34 having reduced diameter end portions 34a. The pin is mounted in the he d 33 on capillary cageless needle rollers 35. In advanceof and to the rear of the p n 34 and equidistant from the axis thereof are torque transmitting rolling pins 36 each having reduced diameter end portions 36a; The pins 35 are also mounted on capillary cageless needle rollers 31 in the head 33. The rollers 36 are disposed with their axes in a plane .through the axis of the roller 34 and normal to the p ston axis. The rolling pins 34 act as'rolling load transmitting means and since each pin carries the direct thrust of the associatedpiston substantially in,

the line of the piston axis, each pin 34 acts as means for reinforcing the associated piston head substantially in the zone of the piston axis.

Rotary reactance rings 38 are provided for coaction with the piston heads and pins and lie alongside the opposite faces of the heads, the rings being seemed together by suitable bolts 33, the accurateaxial spacing of the rings 38 being maintained by spacers 40. The rings, in turn,

are rotatably mounted in a stator 4| which operates in the usual manner. The rings 38' have axially aligned chordal ways, each way comprising a radially wide portion 38a for rolling and oscillating coaction with the ends 34a of the load pin 34, and symmetrical end portions 38b of less radial dimension, the end portions coacting with The specific operation of this structure is best illustrated in Fig. 12. Assuming the barrel to be driven in a clockwisedirectiomit is apparent that the hydraulic loadwill be taken by" the pin 34 which, though oscillating along its slots 38a, applies the load within the projected area 'of the piston; In eiiecting the torque transmission, there is a very slight rocking of the head which causes engagement of the leading roller 36 with the radially inward operating surfaces of the ways 38b,"and the trailing rollers ends 36a of the torque transmitting rolling pins 36 with the outer operating surfaces of the associated ways 38b, thus providing positive torque transmission. Necessarily any-such rocking is about the axis of the pin 34, as illustrated by the dot and dash lines in Fig. 12, but the relative positions of the axes of the pins 36 and the axis of the pistons are necessarily fixed at right.-

angles at all times.

In Fig. 12, the actual clearance between the that the load will be primarily applied by the pin 34 and not by the pins 36.

Obviously, in such a structure, excessive wear would affect the operation and consequently all surfaces are made of non-wearing material such as nitralloy or the equivalent. Preferably nitralloy pins having a surface hardness of 1000 Br nell and reactance rings having corresponding hardness are used, as the wear in such instance is not suflicient to appreciably affect the operation.

Referring next to Figs. 13 and 14, this structure utilizes a circular path of oscillation f1, corresponding to the circle I in Fig. 2, for the p ston connections with the rings of the secondary rotor. In this structure, the cylinder barrel having radial cylinders 46 is shown. Pistons 41 i are carried in the cylinders 46 respectively and each has a head 48 of greater d mension in th direction of load application than. transversely thereof, in the same manner as-the heads heretofore described. The reactance comprises rings 49, which are'mounted for independent axial and floating movement in a stator 50 on free ca eless rollers operating in and guided at the ends by circumferential recesses in the stator. The rings 49 have aligned bores which receive rolling cross-- pins 5|. Each of the pins'5l has an enlarged c' q tral portion, and reduced end portions 5la. The reduced end portions of each pin are mounted on capillary cageless rollers in aligned bores of the rings 49 and extend beyond the outer radial faces of the rings 49. The ends of the pins are recessed to receive snap washers 52 which engage the outer radial faces of the rings and constrain them from axial operation. The larger in proper axially spaced relation by rolling engagement therewith.

Each head 48 has an arcuate slot or operating way 48a which accommodates the enlarged central portion of the associated pin 5| and is in rolling engagement therewith, slight operating clearance being provided. The'operating ways are segments of circles concentric with the rings 49'. The axis of the pin 5| is parallel with the axis of rotation of the barrel and rings 49 and normal to the longitudinal axis of the head. The central portion of the pin 5| is of such diameter relative to the piston that the radial hydraulic piston load will be applied within the projected area of the piston in the arcuate way of the head so that there is a rigid, non-yielding load application between the piston and pin. The tangential rolling reciprocation of the pin inthe way 48a will not be more than the diameter of the piston and as a result of this manner of applying the load, a very light crosshead structure can be utilized so that the inertia of the high speed rotation and reciprocation is reduced. For this same reason, the pistons may be made of duraluminum.

Another very important feature is the simplified movement and relation between the cylinder barrel and the reactance rotor rings. The pistons and heads are preferably made of a single piece of material forged to the proper shape. Due to the fact that the rolling pins 5| are mounted antifrictionally in the rings 49, the resistance to rotation thereof in the rings is less than the rolling frictional engagement of the pins with the operating surfaces of the ways 48a. as a result of which anti-friction rolling cooperation is provided and binding and sliding of the pins in the ways are eliminated. The barrel is mounted on rollers 53 and coacts with a valve pintle 54, sets of full complement rollers 55 and 56 being interposed between the pintle and barrel. In the form illustrated, an impeller 51 is carried on the barrel.

Referring next to Figs. 1'7 to 22 inclusive, there is illustrated a barrel 60 having a radial flange GI and radial cylinders 62 in the zone of the flange. The reactance comprises a stator 63 which rotatably-supports' "axially spaced reactance rings 64. Mounted in each cylinder is a piston 65 having a crosshead 66 which is accommodated between the rings 64 with operating clearance only. The flange 6| has a plurality .of radial guideways 61 aligned with the cylinders respectively, the guideways having cylindrical end walls snugly'engaging complementary end walls of the heads 66 so as to prevent lateral rocking of the heads-and for transmitting torque.

Each head 66 has an arcuate slot or way 66a corresponding to the Way 4811 of the structure of Fig. 14. ,Correspondingly crosspins 68 having relatively large central portions'68a and reduced end portions 68b are mounted in the reactance rings 64 by the reduced end portions. The central portion 68a of each pin is in rolling cooperation with the walls of the way 660, the reduced end portions 66?) being received in aligned bores in-th'e rings 64 and mounted therein on capillary cageless needles 69. The outermost ends of the pins 68 are provided with recesses 68c in which are disposed suitable snap washers .10 for maintaining the pins in the rings 64 and constraining the rings against axial separation. Here again, due to the anti-friction mounting of the ends 68b 7 of the pins 66 in therings 64, rolling cooperation only between the central portion 68a of the pins and the ways 66a is provided.

In this construction there is combined the load application to the piston along a circular path in corresponding to the circle I of Fig. 2, and a piston crosshead which is fixed in relation to the piston, whereas heretofore piston structures in which the load is applied along an, arcuate path employed the pistons which were separated from the heads so as to provide for self-adjustment. This structure is made possible by the cooperation of the head and guideways 61. When the piston and head are separated, as in prior structures, there is a rocking movement with respect to the crosspin and the piston so that the crosshead describes a semi-crank motion which imposes a substantial destructive tangential component of load on the piston through the crosspin, and upon the cylinder walls. In the present structure, however, since the head is well guided and supported by the guideways 61, and unnecessary heavy reciprocating ports are eliminated by mounting the pins in the reactance rings instead of directly in the head, this rocking action is reduced or eliminated and is prevented from reaching the pistons in a degree sumcient to cause wear and binding. The ways 66a necessarily lighten. the reciprocating head so that high speed and high pressures as great as may be necessary may be provided. In all the forms of the invention hereinbefore illustrated, the axes of the rolling pins and the operating ways are disposed at the normal axis of the associated heads.

Referring to Figs. 23 and 24, an unusual operating phenomenon resulting from the use of capillary rollers is shown as mounted between two members X and Y which are relatively rotatable, one such member being a reactance ring or piston head, and the other being a thrust pin. The capillary cageless rollers are disposed between the members X and Y with a total circumferential clearance equal from slightly less than 1 to about.

2 needles. For example, the needles may be packed between the members X and Y and then one or two needles of the full complement removed. The needles operate in an oil bath, which, in the present pump, is provided by slip fluid. Assuming the load to be applied to'the member X, in the direction of the arrows Z1 and Z2 in Figs. 23 and- 24 respectively, an unexpected reaction occurs. It is found that the needles crowd to the loaded zone instead of being driven away or squeezed out from under the load. The needles opposite the loaded zone correspondingly separate circumferentially as indicated by the arrows s. Upon the separating of the needles,

as indicated by the arrows s, the resultant clearance space between the unloaded needles sucks in oil. Obviously in a reciprocating member wherein the load is first applied in one direction as indicated in Fig. 23, and then in the opposite direction as indicated in Fig. 24, full complement bearing for load is provided with a separation of the needles at the unloaded side for receiving oil.

both races due to capillary oil films, and full rolling bearing surfaceat the instantaneous loaded side is provided.

' Having thus described my invention,

I claim: 1. In a hydraulic machine of the class described including. a plurality of rotatable radially disposed piston and cylinder assemblies, the'pistons being reciprocable relatively to the cylinders and having rigid piston heads thereon, a rotary support having radial wall portions lying alongside the piston heads, each piston head being elongated fore and aft from the axis of the associated piston and relatively wide in the plane of the pistons, operating ways in the heads extending entirely therethrough transversely of the heads both fore and aft of the piston axis, transverse rollers for each head mounted at their ends in said radial walls and in rolling cooperation with said ways, said rollersv being positioned in advance and in rear of the piston axis of the associated head, and reinforcing bridges in the heads at the longitudinal midportions of the operating ways.

2. In a hydraulic machine of the class described including a plurality of rotatable, radially disposed piston and' cylinder assemblies, each comprising a relatively reciprocable element and a relatively non-reciprocable element, the relatively reciprocable elements having rigid heads thereon respectively, a rotary support having radial wall portions lying alongside the heads, each head being elongated fore and aft from the axis of the associated piston and cylinder assembly and relatively wide in the plane of the reciprocable elegnents, operating ways in the heads extending entirely therethrough transversely of the heads both fore and aft of the associated piston and cylinder axis, transverse rollers for each head mounted at their ends in said radial walls and in rolling cooperation with said ways, said rollers being positioned in advance and in rear of the 3. In a hydraulic machine of the class described including a plurality of rotatable, radially disposed piston and cylinder assemblies, each comprising a relatively reciprocable element'and a relatively non-reciprocable element, the relatively reciprocable elements having rigid heads thereon respectively, a rotary support having radial wall portions lying alongside the heads, each head being elongated fore and aft from the axis of the associated piston and cylinder assembly, operating ways in the heads extending entirely therethrough transversely of the heads bothfore and aft of the associated piston and cylinderaxis, transverse rollers for each head mounted at their ends in said radial walls and in rolling cooperation with said ways, said rollers being positioned in advance and in rear of the piston and cylinder axis of the associated head, and reinforcing bridges in the heads at the longitudinal mid portions of the operating ways.

4. In a hydraulic machine of the class. de-

scribed including a plurality of rotatable, radially disposed piston and cylinder assemblies, each comprising a relatively reciprocable element and a relatively non-reciprocable element, the relatively reciprocable elements having rigid head members thereon respectively, a rotary support member having radial flange portions lying along- I sociated piston and cylinder axis and each having rolling engagement with the way in one member and being journalled in said other member, and

reinforcing means for said heads substantially in the line of the respectively associated piston and cylinder axes.

ELEK K. BENEDEK. 

